Device located on scrap shears or similar for reducing the frictional forces that occur as a result of the action of the material to be crushed on the closing motion

ABSTRACT

The invention relates to scrap shears ( 1 ) comprising several jaw arms ( 2   a,    2   b,    3 ), which can execute a pivoting motion in relation to one another in a closing or opening direction of the scrap shears. At least one jaw arm is equipped with a counter-bearing element ( 12 ) on the end section lying opposite the mounting ( 4 ), said element being displaced, (at least temporarily), in relation to the jaw arm carrying said element between a working position and a reduced friction position. The counter-bearing ( 12 ) is configured in such a way that the distance between its external surface ( 12   b ), which faces away from the carrying jaw arm and the mating surface ( 3   b ) of the neighbouring jaw arm ( 3 ), which faces towards said external surface, increases with the relative displacement of the counter-bearing element towards the reduced friction position.

The invention relates to a device on a scrap shear or the like forreducing friction created by material being cut encountered when cuttingwhile closing in a direction, the device having several jaws that canpivot relative to each other on opening and closing of the scrap shear,an end section of the scrap shear remote from its mount having at leasttwo adjacent jaw-carrying arms having blades that form a cutting regionthat is reduced on movement in the cutting direction, the arms of theend section laterally overlapping in a closed position of the scrapshear.

Scrap shears and similar cutting devices that are carried for example ona piece of hydraulic equipment serve for cutting and comminuting objectsof steel or the like, in particular metal materials. The simplestsystems are scrap shears with two relatively pivotal jaw-carrying armshaving blades at their outer scrap-cutting ends; a cutting gap formedbetween them decreases as then approach each other. The invention isusable on all types of scrap shears and the like whether or not and howthe jaw-carrying arms are pivoted into the open or closed position.

The scrap shear or the like can be set up such that only one of the armsor both arms are pivotal on the mount, with a single actuator for botharms or one for each arm. In addition the invention is usable with scrapshears or the like with more than two arms, in particular in anembodiment with two outer jaws carried on a double arm and a centraljaw-carrying arm whose end moves on relative movement of the single anddouble arms between the outer jaws. The relative movement between thedouble-jaw arm and the central single-jaw arm can be effected by movingeither the double arm or the central arm relative to the mount carryingthe scrap shear. In embodiments with only one jaw arm movable relativeto the mount the central arm is usually the movable one and thedouble-jaw arm is fixed to the mount. In order to prevent lateraldeflection of the central jaw arm, the jaws of the double-jaw arm whichdefine their side of the cutting gap support wear-resistant slide platesor a blade.

During a cutting operation transverse forces effective perpendicular tothe plane of pivoting are created in the cutting region of the scrapshear by the material being cut and the gap in the cutting regionbetween the acting jaw arms is increased so as to change the geometry ofthe cutting gap and allow the material being cut to get in between. Ifthe transverse force is sufficiently high, the friction between theadjacent jaw arms is enough that it cannot be overcome by the driveforces for operating the scrap shear. The result is that the scrap shearis out of service and the jam must be cleared, a time-consuming anddifficult job.

It is an object of the invention the make it possible to deal with jamsoccurring during cutting by special formation or manipulation of theparts of the scrap shear. The new apparatus should be particularly setup that the scrap shear is less sensitive to frictional forces and theforces to open it even under difficult circumstances are sufficient.

This object is achieved by the features of claim 1. The basic idea ofthe invention is that at least one jaw has an end section remote fromthe mount, may have a blade, and is provided with a support that ismovable at least partially relative to the jaw between a work positionand a pressure-reducing position and the support is constructed suchthat when moved in-to the friction-reducing position a spacing betweenits face turned away from an outer face supporting the jaw and theconfronting face of the adjacent jaw increases. This is the same whenthe spacing between the moving outer face and a relatively fixed supportface of the supporting arm decreases.

Under these circumstances the support element according to the inventioncan be constructed and mounted in many different ways. In particularlythe support element can itself be a blade or can be provided with ablade. Furthermore according to the invention there can be a pluralityof supports formed as blades themselves or as slide plates on adjacentjaw arms.

With regard to the basic object at least one of the existing supports isset up such that it operates either automatically (that is withoutexternal actuation) or can be operated when needed to move into thefriction-reducing position. The term “use position” refers to theposition of the active support during normal use of the scrap shear.Moving the support toward the friction-reducing position reduces thefriction effective on the ends so that any jamming, for example at thestart of opening the shear, is eliminated. By providing the scrap shearwith at least one support which can be moved appropriately on thesupporting jaw arm it is certain that the transverse forces effective inthe cutting region and if necessary other frictional forces are reducedsuch that the scrap shear can be returned to service in short order.

The invention can be basically constituted such that the support can befreely shifted on the jaw arm in order to provide the necessary play.Alternatively in one embodiment the support includes at least onefastener for securing it to the supporting jaw (claim 2). Thisembodiments makes operation easy: Under normal conditions the support issecured by the fastener (for example at least one screw) to the carryingjaw arm in a predetermined position so it cannot move. In case during acutting operation there is a jam, the fastener is released so that thesupport can move into the friction-reducing position. Once the jam iscleared, the support is moved back into the use position. The describedembodiment is set up such that the support is only limitedly movable onthe supporting jaw arm.

Independent of the actual working conditions and requirements, theinvention can also be such that the fastener is remotely operable (claim3). When the fastener is a clamping cylinder which normally fixes thesupport on the carrying jaw arm and if necessary, that is when actuated,lets the support move in the described manner. In the simplest systemthe clamping cylinder is hydraulic; alternatively other fasteners can beused, in particular motor-driven threaded spindles.

It is within the scope of the invention to make the support a wedgewhich can be shifted mainly in the opening direction of the scrap shearrelative to the supporting jaw into the friction-reducing position(claim 4). This embodiment requires that the supporting arm have anappropriate guide face. It must be constructed to coact with the wedgesuch that movement of the wedge in the opening direction of the scrapshear increases the spacing between its outer face and the confrontingface of the adjacent jaw arm. In the simplest case the wedge is bracedsuch on the supporting jaw that the displaced wedge also movestransversely parallel to itself (claim 5).

In another embodiment of the invention the support is shiftableperpendicular to a pivot plane (claim 6). In a further development ofthis embodiment the support is shiftable and arrestable by threadedelements (claim 7). Alternatively the support can be formed as acylinder unit and is operable by a pressurizable fluid (claim 8). Thecylinder unit has a biasing unit that acts against the pressure of thefluid (claim 9). The biasing unit, in the simplest case a mechanicalspring, can be set up that it is effective either toward the use portionor toward the friction-reducing position. Preferably the cylinder unitis displaced by the fluid into a use position in which the supportassumes its use position.

In a further embodiment of the invention the support is pivotal relativeto the supporting jaw such that in the friction-reducing position aspacing between the angled support outer face and a confronting face ofthe adjacent jaw seen in the closing direction of the scrap shearincreases (claim 11). The support is pivoted either by a threadedelement (claim 12) or by an eccentric (claim 13).

It is to be understood that in the scope of the teachings of theinvention if necessary taking into account the actual structure of thescrap shear or similar cutting device, it is possible to use several ofthe above-described embodiments of the invention. This is in particularthe case when the scrap shear or similar cutting device has more thantwo jaw-carrying arms, for example the above-described double arm and acentral arm working with it.

The invention is more closely described in the following with referenceto the drawing; therein there is only shown by way of example a scrapshear with three jaws, namely a double arm carrying two outer jaws and acentral one-jaw-carrying arm pivotal between them. As already described,the invention can also be applied to other cutting devices, inparticular scrap shears having only two jaws.

In particular:

FIG. 1 a is a schematic view of a scrap shear;

FIG. 1 b is a perspective view of the double-jaw-carrying arm and thesingle-jaw-carrying arm of the scrap shear shown in FIG. 1 a;

FIG. 2 a is a largely schematic section through the double jaws and thecentral jaw of a scrap shear according to the invention shown during acutting operation;

FIG. 2 b is a section like FIG. 2 a during opening of the shear;

FIG. 3 a is a largely schematic section through the double jaws and thecentral jaw of a scrap shear according to the invention during a cuttingoperation, where both of the double jaws and the central jaw areprovided with wedges;

FIG. 3 b is a section like FIG. 3 a during opening of the shear;

FIG. 4 a is a largely schematic section through the double jaws and thecentral jaw of a scrap shear according to the invention during a cuttingoperation, where one of the double jaws has a cylinder unit as support;

FIG. 4 b is a section like FIG. 4 a during opening of the shear;

FIG. 5 a is a largely schematic section through the double jaws and thecentral jaw of a scrap shear according to the invention during a cuttingoperation, where one of the double jaws has a support pivotal by aneccentric;

FIG. 5 b is a section like FIG. 5 a during opening of the shear;

FIG. 6 a is a largely schematic section through the double jaws and thecentral jaw of a scrap shear according to the invention during a cuttingoperation, where one of the double jaws has a support pivotal by ascrew; and

FIG. 6 b is a section like FIG. 6 a during opening of the shear.

A hydraulic scrap shear 1 shown in FIG. 1 a has as is known adouble-jaw-carrying arm 2 and a central single-jaw-carrying arm 3 thatare pivotal on a support 4. It in turn is hung on its side opposite thearms 2 and 3 on a rotary mount 5 by means it is connected pivotally toan unillustrated main support, for example a piece of hydraulicconstruction equipment. Whereas the central jaw-carrying arm 3 issingle, the arm 2 is double, having as shown toward the front in FIG. 1a a forward first jaw 2 a and, spaced therefrom, a second jaw 2b shownin the back in FIG. 1 b.

In order to operate the main arms 2 and 3 there are two hydraulicactuators 6 and 7 having respective cylinders 6 a and 7 a pivoted on thebottom of the rotary mount 5 and piston rods 6 b and 7 b pivoted on thedouble arm 2 and the central single arm 3.

Extension of the hydraulic actuators 6 and 7 moves the main arms 2 and3, which in turn are pivoted on the support 4, such that the shear 2closes as shown by arrow 8. Shortening of the hydraulic cylinders 6 and7 effects an opposite pivotal movement of the main arms 2 and 3 so thatthe shear 1 opens.

While the central arm 3 has on its outer edge shown in FIG. 1 a threeblades 9, the first jaw 2 a has on its edge (see FIG. 1 b) threelongitudinally spaced blades 10, that is the blades 9 and 10 areremovably mounted on confronting faces of the central jaw-carrying arm 3and the first jaw 2 a and form the cutting region of the shear 1 as itcloses in the direction of the arrow 8. This is possible because thecentral arm 3 is shorter than the two jaws 2 a and 2 b of the double armand is set up such that on closing its jaw 3 a moves into the spacebetween the jaws 2 a and 2 b; the ends of the adjacent arms similarlyoverlap, namely on the one hand the ends of the jaw 2 a and the arm 3and on the other hand the jaw 2 b and the arm 3 are laterally adjacenteach other on closing.

When, during closing in the direction of the arrow 8 (see FIG. 1 a), thearms 2 and 3 are close enough together, the unillustrated material 11being cut (see for example FIGS. 2 a and 2 b) is pressed by the jaw 3 aagainst the double arm 2 and is cut through by the interaction of therespective blades 9 and 10, with the jaw 3 a moving in between the jaws2 a and 2 b. Since the central jaw-carrying arm 3 is subjected totransverse forces during the cutting operation, it is deflected(transversely) away from the jaw 2 a and inevitably a portion of the cutmaterial will get into the gap between the blades 9 and 10. The resultof this is that the force that can be exerted by the hydraulic cylinders6 and 7 is not enough to open the shear 1 in a direction opposite thatof the arrow 8. The main arms 2 and 3 are thus wedged together as aresult of friction at the gap between the central jaw-carrying arm 3 andthe second jaw 2 b and cannot be opened by operation of the hydraulicactuators 6 and 7, unless the system complies with the instant inventionas described below.

As shown in FIGS. 1 a, 1 b, 2 a, and 2 b the scrap shear 1 according tothe invention has an additional support element constituted as a wedge12 to which a wear-resistant slide plate 12 a is secured byunillustrated fasteners (for example screws). The wedge 12 is mounted,if necessary slidably, on the second jaw 2 b level with the jaw 3 a,more particularly on an inner face of the jaw 2 b confronting the faceof the central arm 3 opposite the face carrying the blades 9. As visiblein FIG. 2 a during a closing movement lateral deflection of the centraljaw-carrying arm 3 is prevented in that its outer face 3 b shown on theright slides on a confronting face 12 b of the slide plate 12 a. Theslide plate 12 a is retained on the second jaw 2 b by guide plates 13and 14 (see FIG. 1 a) such that it assumes during a closing movement aposition between the approaching double-jaw-carrying arm 2 and centralarm 3 generally perpendicular to a longitudinal axis 4 a of the holder4. The extent of travel for the slide plate 12 a and wedge 12 as shownon the left in FIG. 1 a is set by a stop plate 15 fixed also on thesecond jaw 2 b; in the FIG. 1 a position the wedge 12 is bracedlaterally on the stop plate 15 and is fixed by screws 16 on the jaw 2 bcarrying the wedge 12. As described in more detail below, afterloosening the screws, the slide plate 12 a fixed on the wedge can movealong the guide plates 13 and 14 relative to the second jaw 2 b suchthat, starting from the use position shown for example in FIG. 2 a, thedistance between the slide plate 12 a or its working face 12 b from thefirst jaw 21 increases. This is possible because the wedge 12 issupported via a back face 12 c on a complementary guide face 2 c of thesecond jaw 2 b; the two coacting faces 12 c and 2 c are (as shown inFIG. 2 a) oriented such that they form seen in a direction opposite thatof the arrow 8 an acute angle with the plane E in which the shearpivots. In any case the second jaw 2 b and the wedge 12 are connectedtogether, for example by screws and/or bolts, such that the wedge 12 canbe allowed to move relative to the jaw 2 b supporting it and can providea small amount of play between the FIG. 2 a position and a position (seeFIG. 2 b) in which friction is reduced.

FIG. 2 a shows, after the cutting operation and the close-up positionproduced thereby, the position of the double-jaw-carrying arm 2 and thecentral single-jaw-carrying arm 3 with the material 11 in the gap 17between the confronting blades 9 and 10 of the central arm 3 and thefirst jaw 2. The central arm 3 has been shifted laterally as shown bythe arrow 18 as a result of the transverse forces in the cutting gap andbears with its face 3 b the direction of arrow 18 on the face 12 b ofthe slide plate 12 a and via the wedge 12 on the second jaw 2 b. Thewedge is guided on the second jaw 2 b such that the slide plate 12 a andthe wedge can only move parallel in the plane of the view, so that thespacing of the face 12 b changes with respect to the first jaw 2 a; thesame is true for the spacing between the first jaw 2 a and the centralarm 3 so long as the same engages the slide plate 12 a. In the workingposition of FIG. 2 a the wedge 12 bears with its narrow end turned awayfrom the arm 3 on the stop plate 15 (shown in FIG. 1 a).

The friction created by the material 11 being cut in the cutting gap 17and between the central arm 3 and the slide plate 12 a leads in certaincircumstances to a situation wherein the double arm 2 and the centralarm 3 cannot be moved by the hydraulic actuators 6 and 7 and the shear 1is jammed. In order to unjam it, one first loosens the screws 16 (shownin FIG. 1 a) so that the slide plate 12 a and the wedge 12 can slide onthe second jaw 2 b. The central arm 3 and the slide plate 12 a arepressed solidly together, but now the forces tending to open the shear 1do not have to overcome friction between the arm 3 and the slide plate12 a, but only have to overcome a lesser amount of friction between thefaces 2 c and 12 c. In this case the applied forces are enough to shiftthe central arm 3 relative to the double arm 2, moving the slide plate12 a and the wedge 12 together with the central arm 3 and, as a resultof the parallel shifting of the slide plate 12 a relative to the secondjaw 2 b, the spacing between the slide plate 12 a and the first jaw 2 aincreases. This increase in the gap has the result of reducing theforces jamming together the double arm 2 and the central arm 3 and thusunloads the entire system formed by the parts 2, 3, 12 a, and 12. FIG. 2b shows this situation for the shear, after the screws 16 have beenloosened the double arm 2 and the central arm 3 are moved in the openingdirection (opposite arrow 8) and the slide plate 12 a and the wedge 12are moved along with the central arm 3 (that is upward in the drawing).In order to make these movements clear the working position (shown inFIG. 2 a) of the parts 12 and 12 a, which is the starting position ofthe central arm 3, is also shown in dot-dash lines.

The invention thus makes it possible to eliminate an occasional jam withrelatively simple and inexpensive means. It is also within the scope ofthe invention to make the slide plate 12 a and the wedge 12 a singlepart and thus form the face 12 c directly on the slide plate 12 a. Inaddition the central arm 3 can carry on its face turned toward the slideplate 12 a a wear-resistant insert, in particularly a removable wearplate. Independently of this, it is advantageous according to theinvention when the wedge 12 or a wedge-shaped slide plate 12 a, issecured on the second jaw 2 b, for example by means of a hydrauliccylinder, and is remotely controllable. The inventive solution alsoencompasses embodiments wherein the slide plate 12 a and wedge 12 or thecombined wedge and slide plate are not fixed but are right from thestart mounted so they can move limitedly on the jaw 2 b.

As shown in the embodiment of FIGS. 3 a and 3 b each jaw 2 a, 2 b, and 3is provided with a support shaped as a wedge, the wedges being differentand the second jaw 2 b being the same as shown in FIGS. 2 a and 2 b. Atleast one of the blades 10 is removably mounted on a wedge 19 bearingvia a face 19 a on a complementary face 20 a of the first jaw 2 a. Theextent of movement of the wedge 19 toward the supporting wedge 2 a (thatis downward in FIG. 3 a) is set by a stop surface 20 a. As alreadydescribed, the wedge 19 can be constructed such that it can be clampedby unillustrated fasteners on the supporting jaw 2 a in the use position(shown in FIG. 3 a).

The central arm 3 is provided in the region that during cutting formsthe cutting gap 17 with a wedge 21 that is slidable on the arm 3 andthat if necessary also can be fixed by an unillustrated fastener. Acavity of the wedge 21 receives a wedge-shaped guide 22 of the centralarm 3. In the use position shown in FIG. 3 a the inwardly directed faces21 a and 21 b sit on the complementary support faces 22 a and 22 b ofthe wedge-shaped guide 22. The latter is constructed such that it tapersin the direction of the arrow 8. The wedge 21 has on its face turnedtoward the jaw 2 a at least one removably mounted blade 9.

FIG. 3 b shows a situation of the shear wherein, if necessary afterloosening any clamping, the jaws 2 a and 2 b on the one side the centralarm 3 on the other are shifted relative to each other in the openingdirection (against the arrow 8). Since as the opening movement of theshear takes place, the wedges 12, 19, and 21 shift both longitudinallyand transversely relative to the supporting jaws 2 b, 2 a, and 3, theentire system (around the cutting gap) can be opened very quickly.

The embodiment of FIGS. 3 a and 3 b can also be varied within the scopeof the invention in that only two of the three jaws 2 a, 2 b, and 3 areprovided as shown with wedges, for example the outer jaws 2 a and 2 b ofthe double arm. Furthermore in order to clear jams it can be sufficientwhen only the central jaw is provided with the wedge 21. The first jaw 2a can be as shown in FIG. 2 a; the second jaw 2 b has no wedge 12 and isprovided on its face turned toward the central arm 3 only with the slideplate 12 a that is fixed by unillustrated fasteners on the second jaw.

Occasional jams can also be dealt with according to the invention inthat at least one jaw of the shear is mounted on a support displaceabletransversely to the closing plane. In the embodiment according to FIGS.4 a and 4 b the second jaw 2 b is provided on its face turned toward thecentral arm 3 with a transversely slidable support formed as a cylinderunit 23; it is comprised mainly of a housing 23 a fixed on the secondjaw 2 b and a piston 23 b movable in it in a seal 23 c. The parts 23 ato 23 c define an internal compartment 23 d that is pressurized withhydraulic fluid through a port 23 e or if necessary depressurized. Thestroke of the piston 23 b in the housing 23 a toward the centraljaw-carrying arm 3 is limited by stops 24 fixed on the housing 23 a. Thepiston 23 b carries on its side turned away from the chamber 23 d aslide plate 12 a. As shown in particular in FIG. 4 b, the cylinder unit23 and the slide plate 12 a are relatively oriented to each other suchthat the abutments 24 lie in every case outside the path of the centralarm 3.

In the embodiment according to FIG. 4 a the cylinder unit 23 is in itsuse position in which the piston 23 b bears on the stops 24 and thecentral arm 3 bears via its face 3 b on the face 12 b of the slide plate12 a. The chamber 23 d is pressurized with fluid. In contrast, FIG. 4 bshows a condition in which the piston 23 b has shifted inside thehousing 23 a (to the right in the drawing) so as to reduce friction, atthe same time increasing the spacing for example between the face 12 band the first jaw 2 a. This transverse shifting of the piston 23 b ismade possible and is in fact initiated by depressurization of thechamber 23 d through the port 23 e in that the central arm 3 as a resultof the transverse forces effective in the cutting gap deflect itlaterally and the slide plate 12 a shifts with the depressurized piston23 b into the described position such that subassembly of the jaws 2 a,2 b, and 3 and the cylinder unit 23 is unloaded in particular in theregion of the cutting gap 17.

It is within the scope of the invention to modify the embodiment ofFIGS. 4 a and 4 b such that the cylinder unit 23 on the second jaw 2 bcan also have a biasing unit effective on the piston 23 b. This iseffected as a mechanical spring support and is effective in that thedepressurized piston 23 b assumes inside the housing 23 a the retractedfriction-reducing position (shown to the right in the drawing). The useof a biasing unit can be advantageous in that it increases thedeflection of the central arm 3 and thus helps unload the entire systemin particular in the cutting gap 17.

It is to be understood that the cylinder unit in the solution accordingto the invention can also be double acting so that the piston 23 can bemoved by appropriate pressurization into the FIG. 4 a use position orthe FIG. 4 b pressure-reducing position.

This embodiment (according to FIGS. 4 a and 4 b) can also be madeaccording to the invention in that the chamber 23 d is connected via theport 23 e to a press with a viscose agent (in particular lubricantgrease) and in the event of a jam the port 23 e is opened so that theviscose agent can be pushed out by the piston 23 b. This embodiment hasthe advantage that it can be done with simple normally already provideddrive units (for example a hand-operated lubricant gun), is not likelyto fail, and is easy to use in case of a jam, for example by opening avalve that vents the port 23 e and thus the chamber 23 d.

The embodiment according to FIGS. 4 a and 4 b can also be simplifiedaccording to the invention in that the support is shifted by threadedelements but otherwise is fixed. This can be done in particular in thatthe piston 23 b is shifted and fixed inside the housing 23 d byunillustrated screws. The screws are threaded into the piston 23 b andbear on the housing 23 a so that the piston 23 b is shifted according tothe rotation direction of the screws either toward the use position(FIG. 4 a) or toward the retracted friction-reducing position (FIG. 4b).

It is possible according to the invention to achieve the desiredreduction of the friction created by the material being cut further byproviding at least one of the jaw-carrying arms at its end remote fromthe mount with a support that is pivotal in a certain manner on the armcarrying it. In the embodiment according to FIGS. 5 a and 5 b the secondjaw 2 b carries a support 25 that is formed of the following parts: aU-section base plate 25 a, a pivot plate 25 b pivoted at one end on it,a slide plate 12 a fixed on it, and an arrestable eccentric 25 c thatcan pivot the pivot plate 25 b relative to the base plate 25 a. While an(unillustrated) pivot joint is provided between the parts 25 a and 25 bat the end of the base plate 25 a closer to the central arm 3, theeccentric 25 c is at the opposite end, the pivot plate 25 b having anend face 25 d engaging more or less into the base plate. FIG. 5 a showsthe pivot plate 25 b when pressed by the arrestable eccentric 25 c intothe use position in which the face 12 b of the slide plate 12 a extendsparallel to the pivot plane E or to the first jaw-2 a.

Rotation of the eccentric 25 c counterclockwise moves the pivot plate 25b bearing on the eccentric 25 c such that the end face 25 d moves backtoward the base plate 25 a and the pivot plate as well as the face 12 dform an acute angle with the pivot plane E. Starting in the use positionof FIG. 5 a the pivot plate is moved by rotation of the eccentric 25 cinto the FIG. 5 b into the friction-reducing position so that the gapbetween the face 12 b and the first jaw 2 a is increased and the cuttinggap 17 is unloaded. It is understood that the slide plate 12 a ismounted on the pivot plate 25 b such that its pivoting on the base plate25 a in any case provides sufficient gap increase for the first jaw 2 a.In addition the above-discussed embodiment is handy in that the pivotplate 25 b can be set up such with respect to the eccentric 25 c thatthe rotation is followed and the base plate 25 a can be swung in eitherdirection relative to the base plate 25 a.

The embodiment of FIGS. 6 a and 6 b of the invention is different fromthat according to FIGS. 5 a and 5 b in that the angular position of thesupport 25 is effected by a threaded element comprises of at least oneadjustment screw 26. Otherwise the pivotal support corresponds generallyto the embodiment with the eccentric.

Starting in the use position (FIG. 6 a) in which at least one adjustmentscrew 26 is at its maximum depth in the base plate 25 a, the angle ofthe pivot plate 25 b and the slide plate 12 a to the pivot plane E ischanged by turning of at least one of the adjustment screws 26 so as tomove it steplessly outward into a friction-reducing position (FIG. 6 b).The pivoting of the pivot plate 25 b toward the friction-reducingposition has the result that the spacing between the face 12 b of theslide plate 12 a and the first jaw 2 a is increased. As a result thecentral arm 3 can deflect and reduce the pressure in the cutting gap 17between the blades 9 and 10; this reduction entails a reduction in thefriction resisting opening in the opening direction (against arrow 8)between the jaws 2 a and 3 or 3 and 2 b and thus makes further operationof the shear possible. As in the embodiment according to FIGS. 5 a and 5b at least one of the adjustment screws 26 is connected with the pivotplate 25 b so that this adjustment screw 26 can forcibly move the baseplate 25 b into the use position or into the friction-reducing position.

It is understood that the support 25 according to the invention can beprovided with other adjustment elements. Furthermore it is possibleaccording to the invention to operate the adjustment elements remotelyby a motor and to lock them in the determined positions.

The advantage of the system of this invention is that equipping at leastone arm of the scrap shear or a similar cutting apparatus with at leastone movable support element makes it possible to reduce pressure in theentire system around the cutting gap that is caused by the materialbeing cut. Similarly the one or more support elements are provided onthe end of the arm remote from its support such that the distance to theadjacent arm can be made larger so that the face turned away form thearm of the support element moves relative to the supporting arm. Afurther advantage of the solution according to the invention is that anoccasionally occurring jam can be cleared without dealing with thecutting region and without having to take apart and reassemble the armstructure.

1. A device on a scrap shear (1) or the like for reducing frictioncreated by material (11) being cut encountered when cutting whileclosing in a direction (arrow 8), the device having several jaws (2 a, 2b, 3) that can pivot relative to each other on opening and closing ofthe scrap shear (1), an end section of the scrap shear (1) remote fromits mount (4) having at least two adjacent jaw-carrying arms (2 a, 3; 3,2 b) having blades (9 and 10) that form a cutting region that is reducedon movement in the cutting direction (arrow 8), the arms (2 a, 3, or 2b, 3) of the end section laterally overlapping in a closed position ofthe scrap shear (1), characterized in that at least one jaw (2 a, 2 b,3) has an end section remote from the is mount (4), may have a blade (9or 10), and is provided with a support (19, 12, or 21) which is movableat least partially relative to the jaw (2 a, 2 b, 3) between a workposition and a pressure-reducing position and the support is constructedsuch that when moved into the friction-reducing position a spacingbetween its face turned away from an outer face supporting the jaw (2 a,2 b, 3) and the confronting face of the adjacent jaw increases.
 2. Theapparatus according to claim 1, characterized in that the support (12,25) includes at least one fastener (16, 26) for securing it to thesupporting jaw (2 b).
 3. The apparatus according to claim 2,characterized in that the fastener is remotely operable.
 4. Theapparatus according to one of the preceding claims, characterized inthat the support is a wedge (12, 19, 21) which can be shifted mainly inthe opening direction of the scrap shear (1) relative to the supportingjaw (2 b, 2 a, 3) into the friction-reducing position.
 5. The apparatusaccording to claim 4, characterized in that the wedge (12, 29, 21) isbraced such on the supporting jaw (2 b, 2 a, 3) that the displaced wedgealso moves transversely parallel to itself.
 6. The apparatus accordingto one of claims 1 to 3, characterized in that the support (23) isshiftable perpendicular to a pivot plane (E).
 7. The apparatus accordingto claim 6, characterized in that the support is shiftable andarrestable by threaded elements.
 8. The apparatus according to claim 6,characterized in that the support is formed as a cylinder unit (23) andis operable by a pressurizable fluid.
 9. The apparatus according toclaim 8, characterized in that the cylinder unit (23) has a biasing unitthat acts against the pressure of the fluid.
 10. The apparatus accordingto one of claims 8 and 9, characterized in that the cylinder unit (23)is displaced by the fluid into a use position in which the supportassumes its use position.
 11. The apparatus according to one of claims 1to 3, characterized in that the support (25) is pivotal relative to thesupporting jaw (2 b) such that in the friction-reducing position aspacing between the angled support outer face (12 b) and a confrontingface (3 b) of the adjacent jaw (3) seen in the closing direction (arrow8) of the scrap shear (1) increases.
 12. The apparatus according toclaim 11, characterized in that the support (25) is pivoted by athreaded element (26).
 13. The apparatus according to claim 11,characterized in that the support (25) is pivoted by an eccentric (25c).